Metformin usually begins lowering blood sugar about 3 hours after taking a dose. However, the full effect on HbA1c levels, which are used to monitor long-term treatment response, is typically seen only after about 3 months of continuous use.
This medication is considered very effective at reducing blood sugar. Still, lifestyle changes such as following a balanced diet, losing weight, and exercising regularly are also important for maintaining good glucose control.
To determine if treatment for type 2 diabetes is effective, it is important to have regular checkups with a doctor. In some cases, other medications may be prescribed along with metformin to achieve better diabetes control.